The EPA data cover vehicles weighing less than 8,500 pounds or less. Sales of SUVs and pickups weighing more than 8,500 pounds but less than 10,000 pounds have grown since 1975. Without including them we can’t really tell how much fuel economy has fallen in the past two decades or whether it might be rising in the last few years (when sales of large SUVs and pickups have declined).

To the extent that falling fuel economy is thought to reflect bad behavior by automakers, they are all guilty. The graph shows (3-year moving average) weight and fuel economy for GM and Toyota.

Between 1975 and 1985

GM improved fuel economy by more than 10 mpg, largely by cutting their average vehicle weight by more than 1,000 pounds.

GM has restored about 900 pounds to average weight, and reduced fuel economy by about 1.5 mpg.

Toyota has added more than 1,000 pounds of vehicle weight, and reduced fuel economy by about 2.5 mpg.

Walter is the Director of the Automotive Analysis Division of the University of Michigan Transportation Research Institute (UMTRI). He studies the adoption by consumers and automakers of new powertrain (electric, hybrid, clean diesel, fuel cell, alternative fuels), safety, and telematics technologies. Walter worked for General Motors for 9 years in sales forecasting, product development, marketing, and manufacturing (1993 found him on the floor of one of GM’s component factories). Prior to joining the University, he was Executive Director of Forecasting and Analytics for J.D. Power and Associates. He earned his doctorate in Economics from UCLA in 1983

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Guest

My 1986 Buick Century with a 2.5 liter, 150 hp four banger got about 36 MPG highway. My 1993 Olds sedan, with a 3.8 liter V6 got about 30 MPG highway, and my 2004 Toyota Avalon with a 3.0 liter 210 hp V6 gets about 28 MPG highway. So besides weight, it appears the big 3 have been ramping up the horsepower for sales advantage, but the fruit is bad, a loss in my experience of about 7 MPG.

Guest

Walter, could you list 2 or 3 examples of “SUVs and pickups weighing more than 8,500 lbs” for me. Edmunds.com posts vehicle weights and the Ford Expedition, Hummer H2, and Chevy Suburban and other similarly large SUVs run less than 6,400 lbs. The 3 listed weigh in at 5,350 lbs, 6,400 lbs, and 6,330 lbs, respectively. I only ask because these are already included int he standard calcs and I am not sure that there are really that many vehicles over 8,500 lbs being sold. thanks.

rafael_g_seidl

If today’s engines were paired with yesteryear’s auto bodies, fuel economy would be 15-20% better than it was. Instead, carmakers all over the world (incl. here in Europe) have chosen to increase the size and weight of vehicles, effectively negating these gains.

Reasons:
(a) tougher crash safety laws (US carmakers are not allowed to assume passengers are wearing seatbelts, eliminating a critical system in crash safety design, leading directly to higher vehicle mass – not so in Europe)
(b) consumer preference for heavier vehicles due to greater presumed safety in a crash, especially if the other party is an SUV or pick-up
(c) tougher acoustic emissions laws (in Europe)
(d) consumer preference for larger engine displacement which are quieter at the typical load actually required, and rumble at lower frequencies which are perceived as a mark of quality
(e) consumer preference for vehicles with quiet interiors, requiring substantial acoustic damping material
(f) consumer demand for comfort and convenience systems (A/C, electric windows, electric seats, navigation systems, sunroof etc.)
(g) increased average height and girth of passengers
(h) consumer demand for increased cargo space

In short, as consumers became more affluent, they had more money available for transportation and also demanded more safety. Until 2002, fuel economy was more or less irrelevant for US consumers because the gasoline was so cheap. Even today, weight for weight, it costs less than bottled water there.

In addition, the average age of the vehicle fleet is going up due to improved product quality – that means carmakers only have one chance per decade per customer to sell a vehicle, so of course they try to sell you the most expensive one they can. That usually means larger, heavier and loaded with more features.

Also, the Hummer H3, the new Hummer offering, is smaller than the H2, weighing in at only 5,350 GVRW. The H1, which is no longer available after 2006, weighs in at 10,000 lbs, but sells for over $130,000, but probably not enough of these were sold to effect the milage calcs to significantly. This actually suports the conclusion that automakers are moving to smaller more gas efficient models.

Guest

Walter,

What about a weighted average that accounts for each makers total sales of each vehicle in computing the actual fleet average. A real world fleet if you will. It would have to be done at the end of year. Does this exist.